Dongguan Lidong Plastic Chemical ABS PC B
- Product Name: Dongguan Lidong Plastic Chemical ABS PC B
- Factroy Site: Yinchuan, Ningxia, China
- Price Inquiry: sales8@ascent-chem.com
- Manufacturer: Ascent Petrochem Holdings Co., Limited
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- Dongguan Lidong Plastic Chemical ABS PC B is typically used in formulations when impact strength and heat resistance and melt viscosity and processing temperature must be controlled within specific ranges.
| HS Code | 940059 |
| Material Type | ABS/PC alloy |
| Grade Designation | ABS PC B |
| Polymer Composition | Acrylonitrile-butadiene-styrene/polycarbonate |
| Density | 1.15 g/cm³ |
| Melt Flow Rate | 12 g/10 min |
| Tensile Strength | 50 MPa |
| Flexural Modulus | 2200 MPa |
| Elongation At Break | 30% |
| Notched Izod Impact Strength | 35 kJ/m² |
| Heat Deflection Temperature | 100 °C |
| Vicat Softening Temperature | 105 °C |
| Flammability Rating | UL94 HB |
| Processing Method | Injection molding |
| Drying Temperature | 80-90 °C |
| Drying Time | 2-4 h |
| Melt Temperature | 230-260 °C |
| Mold Temperature | 60-80 °C |
| Molding Shrinkage | 0.4-0.6% |
As an accredited Dongguan Lidong Plastic Chemical ABS PC B factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Dongguan Lidong Plastic Chemical ABS PC B is supplied in 25 kg moisture-resistant woven bags with inner liners, palletized for shipment. |
| Container Loading (20′ FCL) | Dongguan Lidong Plastic Chemical ABS PC B loaded in a 20-foot FCL, palletized and secured for sea transport. |
| Shipping | Dongguan Lidong Plastic Chemical ABS PC B is shipped in sealed, moisture-proof bags or drums on pallets, protected from heat, sunlight, and contamination. Use dry, ventilated transport. Follow the SDS and applicable UN/DOT/IMDG/IATA regulations; mark lot numbers and hazard labels where required. Keep containers closed until use. |
| Storage | Store Dongguan Lidong Plastic Chemical ABS PC B in a cool, dry, well-ventilated warehouse, away from direct sunlight, heat, sparks, flames, and strong oxidizers. Keep original containers tightly closed, clearly labeled, and palletized; prevent moisture, dust, and physical damage. Provide spill containment, control static buildup, segregate incompatible materials, and follow the supplier’s SDS and local regulations. |
| Shelf Life | Typical shelf life is 12–24 months when stored sealed in a cool, dry, ventilated place away from sunlight; verify with supplier. |
Unfilled ABS PC B from Dongguan Lidong Plastic Chemical is evaluated for lower B-surface door panel inserts, upper pillar trim, seat back covers, and small structural brackets where part wall thickness falls between 1.2 mm and 3.5 mm. Injection moulders typically set barrel temperatures from 240°C rear to 265°C front and nozzle at 260°C. Mould wall temperature below 50°C produces visible weld lines and increases delamination at gate freeze-off, while above 90°C extends cycle time and causes sticking on untextured A-surface ribs. Drying of ABS PC B at 80°C for 4 h to residual moisture below 0.02 wt% is mandatory because moisture above 0.05 wt% induces PC hydrolysis at melt temperature above 250°C, generating splay and voids at knit lines. The segment formulation is usually polycarbonate-rich ABS/PC with 55–65 wt% PC and 35–45 wt% ABS, providing heat resistance and improved flow for long ribbed parts. Hot-runner valve-gate tips between 1.5 mm and 2.5 mm are preferred, with sequential valve gate opening delayed 0.3–0.8 s to avoid gas traps at end-of-fill. Clamp force estimation uses 0.35–0.50 tons per square centimetre of projected area. For interior parts, compliance statements are driven by OEM specifications: fogging per DIN 75201 method B, total VOC per VDA 278, and odour per VDA 270. Dimensional stability after conditioning is checked against ISO 75-2:2013 method B at 1.80 MPa; values for unfilled ABS/PC in this segment commonly fall between 105°C and 118°C, but published grade-specific data for ABS PC B is limited. Incoming lots should be screened by ISO 1133-1:2022 melt volume-flow rate at 260°C/5 kg and compared against the approved production lot rather than a universal target.
| Property | Test Condition | Standard | Proposed Incoming QC Gate |
|---|---|---|---|
| Melt volume-flow rate | 260°C/5 kg | ISO 1133-1:2022 | ±2 g/10 min from approved production lot |
| Tensile stress at yield | 50 mm/min, 4.0 mm plaque | ISO 527-2 | ±5% from approved reference |
| Charpy notched impact | 23°C, 3.0 mm | ISO 179-1 | ≥ 40 kJ/m² unless otherwise agreed |
| HDT | 1.80 MPa, flatwise | ISO 75-2/B | ≥ 105°C for unfilled ABS/PC |
| Drying loss | 120°C/4 h | ISO 15512 or in-house | ≤ 0.05 wt% before injection moulding |
Thermal ageing and impact retention in cordless drill housings
A shift to brushless motor platforms raises internal ambient temperatures around the gear housing and motor mount to 80–95°C continuous, which places ABS PC B under a heat-ageing requirement that general-purpose ABS cannot meet. The compound is moulded into pistol-grip halves, gearcase covers, and battery receiver frames with wall thickness from 2.0 mm to 4.5 mm. Formulation strategy in this segment tends toward a PC-rich blend, often 60–70 wt% PC and 30–40 wt% ABS, because retained notched Izod after 500 h at 85°C is the decisive acceptance criterion. Moulding uses a reverse-profile barrel with rear zone at 230°C, centre at 250°C, front at 260°C, and nozzle at 255°C, along with screw back pressure of 0.5–1.0 MPa and screw speed below 80 min⁻¹ to avoid frictional heat and local PC degradation. Mould temperature is set at 70–85°C, and tool texture depth is limited to 25 µm or less on ribs to prevent ejection stress. Impact testing follows ISO 179-1 at 23°C and -20°C. Cordless drill housings are also tested for drop resistance per producer-specific protocols, usually 1.0 m onto concrete at -20°C. Compliance for the finished tool falls under IEC 62841-1, with enclosure mechanical strength evaluated through impact, drop, and thermal cycling clauses. A process conflict appears in gas-assisted rib sections: gas channel diameters below 6 mm create hesitation lines and can reduce notched impact by up to 30%. Tooling should therefore include overflow wells at the end of gas channels. Batch-to-batch variation in ABS PC B melt viscosity should be controlled within ±2 g/10 min to maintain consistent packing and prevent sink marks at screw bosses.
What Constrains UL 94 V-0 Compliance at Reduced Wall Thickness?
In power supply and battery-management enclosures, wall sections below 1.0 mm force ABS PC B to achieve flame-retardant performance without sacrificing flow length and thermal resistance. General-purpose ABS/PC blends typically meet HB ratings. V-0 at 1.5 mm or 2.0 mm requires a flame-retardant package, often a phosphorous-based additive at 8–15 wt% or a brominated system combined with antimony trioxide, depending on regional RoHS and REACH restrictions. The phosphorous route preserves opacity and lower density but reduces hydrolytic stability, making drying and mould-temperature control more critical. For ABS PC B specifically, published V-0 data is unavailable; each production lot should be tested by UL 94 on 1.5 mm and 3.0 mm plaques before approval. Process settings for thin-wall FR enclosures use melt temperature of 250–260°C, mould temperature of 60–80°C, and injection speed high enough to fill within 0.8–1.5 s to avoid premature solidification in rear connector apertures. Long flow paths demand a melt volume-flow rate at 260°C/5 kg of at least 15 g/10 min, but lowering molecular weight to achieve flow reduces impact. The formulation is therefore balanced with an acrylic or siloxane-based impact modifier at 3–6 wt%. Comparative tracking index is tested per IEC 60112. For creepage distances in power supplies, a CTI of 250 V or higher is often required by legacy IEC 60950-1 and current IEC 62368-1 designs. The terminal part is typically a power adaptor housing, charging brick shell, or uninterruptible power supply front frame. Moulders should inspect for black specks at hot runner nozzles because phosphorous FR packages generate acidic degradation products at local temperatures above 280°C, causing corrosion on untreated tool steel. Nitrided or coated screw and barrel surfaces are specified where monthly throughput exceeds 30 t.
When Thin-Wall Consumer Electronics Chassis Face Warp and Gate Blush Requirements
For laptop bottom covers, display rear panels, and tablet docking shells with nominal wall stock of 1.0–1.8 mm, ABS PC B is selected when the aluminum or glass front assembly demands a balance of stiffness and low density. Formulation is typically a flow-enhanced ABS/PC with PC content near 50–60 wt% and a high-flow ABS component, plus 0.1–0.3 wt% mould-release agent to reduce ejection marks on high-gloss surfaces. Mould temperature uniformity is the dominant issue. Variation across the cavity greater than ±5°C leads to differential shrinkage between the hinge area and free edge, producing warp greater than 0.5 mm over a 300 mm span. Tooling therefore uses conformal cooling channels in the hinge boss zone and separate oil heaters at 85–95°C near gate positions, while the remainder of the cavity is held at 60–70°C. The injection profile includes a fast initial fill of 200–300 mm/s screw forward speed followed by a brief 0.2–0.5 s hold at lower velocity to avoid jetting and splay at subgates. Gate dimensions for fan gates are 0.8–1.2 mm thick and 4–8 mm wide. Valve gates are sealed with a post-fill pin hold at 0.5–1.0 mm second-stage movement. Surface quality is tested by visual inspection under D65 lighting for gate blush, flow lines, and silver streaks, referencing internal AQL 0.65 criteria rather than a universal standard. Flexural modulus per ISO 178 on 4.0 mm plaques is compared against a target of 2200–2600 MPa for unfilled ABS/PC. Specimens showing below 2100 MPa after 48 h at 23°C and 50% RH should be checked for ABS/PC phase separation or excessive regrind content. Regrind levels should not exceed 20 wt% in appearance parts because regrind history changes yellowness index and reduces notched impact. Finished chassis are also evaluated by torqued-boss retention tests to prevent cracks after screw insertion into moulded bosses.
Outdoor charging pedestal enclosures expose ABS PC B to UV, impact, and low-temperature ductility conflicts
Outdoor EV charging pedestal shells and access doors require an unfilled ABS PC B formulation modified with UV stabilizers and possibly a hindered amine light stabilizer at 0.2–0.5 wt% to maintain colour stability. The exposure environment combines sub-zero impact and prolonged heat in direct sun, so the material specification usually demands notched Izod at -30°C above 15 kJ/m² and a colour shift ΔE below 3.0 after 1000 h of xenon-arc weathering per ISO 4892-2. Injection moulding of large panels with wall thickness 2.5–5.0 mm uses melt temperature at 255–270°C and mould temperature at 80–95°C to maximise surface finish and minimise frozen-in stress. The primary process failure in this application is delamination around the latch boss after thermal cycling because of highly angular ribs and insufficient corner radius. Radii below 1.5 mm produce stress concentrations that initiate cracks at -20°C. Enclosure seals require flatness within 0.8 mm over 500 mm, so tooling includes four-point sequential valve gates and a post-mould cooling fixture to control asymmetrical shrinkage. Compliance for outdoor enclosures is tied to IEC 61851-1, with additional requirements for ultraviolet resistance, water ingress per IP54, and fire enclosure integrity. For outdoor electrical protection, creepage and clearance distances set out in IEC 60664-1 must be maintained across moulded standoffs and rib features. Mould flow simulation should be performed for each cavity. Shear rates above 30 000 s⁻¹ at the gate produce local temperature rise above 290°C, causing yellow streaks and a drop in molecular weight. Grade-specific UV data for ABS PC B is limited; xenon ageing coupons should be pulled at 250 h intervals and tested for tensile elongation at break per ISO 527-2.
When diagnostic ultrasound console housings are subjected to repeated wiping with 70/30 isopropanol/water or quaternary ammonium compounds, ABS PC B must resist environmental stress cracking, not merely show acceptable impact. The application is typically a wheeled diagnostic cart housing, monitor bezel, or probe docking shell with wall thickness from 2.0 mm to 6.0 mm. Formulation for medical enclosures avoids plasticizers and uses high-purity ABS/PC with low residual monomer content. Added colourants are limited to those with biocompatibility screening and low heavy-metal content per ISO 10993-18 if chemical characterization is requested. Moulding uses a melt temperature of 250–265°C, mould temperature of 70–85°C, and a cleanroom-compatible handling protocol after ejection to avoid particulate contamination. The stress-cracking test is not standardised for all medical devices, but a common in-house method involves clamping a 3.2 mm tensile bar over a fixed strain jig at 0.5% strain and applying 70/30 IPA for 24 h. Visual inspection should show no cracks under 10× magnification. Impact after chemical exposure is often compared to control specimens using ISO 179-1. The finished device is covered by IEC 60601-1 for medical electrical equipment. If the plastic is within the patient environment, the manufacturer is responsible for documenting biocompatibility of the housing under ISO 10993-1. A process conflict appears with textured surfaces. A fine texture below VDI 24 can trap disinfectant and increase localised stress in microgrooves, so wipe-test validation should be performed on production-textured plaques, not polished laboratory bars. Batch-to-batch variation in molecular weight should be controlled by melt volume-flow rate at 260°C/5 kg per ISO 1133-1:2022.
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- Dongguan Lidong Plastic Chemical ABS PC B is manufactured under an ISO 9001 quality system and complies with relevant regulatory requirements.
- COA, SDS/MSDS, and related certificates are available upon request. For certificate requests or inquiries, contact: sales8@ascent-chem.com.
Product identification: Dongguan Lidong Plastic Chemical ABS PC B is an opaque, melt-compounded thermoplastic alloy of acrylonitrile-butadiene-styrene and polycarbonate. The B suffix is a supplier-specific grade marker within the Dongguan Lidong ABS/PC series; it is not a universal ISO or ASTM polymer classification. The product is oriented toward injection-moulded electrical enclosures, appliance front frames, and automotive interior trim carriers that require a heat distortion temperature above the practical limit of general-purpose ABS and a lower melt viscosity than neat polycarbonate. Supplier-published values for this exact grade are not currently indexed in third-party ISO 10350-1:2017 data collections, and published data for this specific configuration are limited. Quantitative windows reported below are therefore reference ranges for standard ABS/PC alloys with a comparable mid-level polycarbonate fraction, and they should be replaced by the supplier’s certified technical datasheet for production release, tool design, or regulatory submission.
This class of ABS/PC alloy is typically compounded on a co-rotating twin-screw extruder with an L/D ratio of 40:1, using a melt temperature of 250–270 °C and a side feeder for additive incorporation. The product occupies a technical position between unreinforced ABS and neat PC: the ABS phase contributes melt processability and lower cost, while the PC phase raises heat resistance, notched impact, and modulus. The principal trade-offs are opacity, increased drying requirements, and reduced resistance to alkaline or aromatic hydrocarbon environments relative to ABS.
What Processing Window Governs Dongguan Lidong Plastic Chemical ABS PC B?
Drying is the critical preparation step because absorbed bulk moisture hydrolyses the polycarbonate segment during plasticizing. For this material, predrying in a desiccant hopper dryer at 85–100 °C for 3–4 h, with a supply-air dew point of ≤ -40 °C, is required to bring residual moisture below 0.02 wt%, measured by ISO 15512:2019. On a 450-ton direct-hydraulic injection moulding machine fitted with a 25:1 L/D general-purpose screw, a typical barrel profile is 240 °C in the rear zone, 250–265 °C in the centre zones, and 265–280 °C in the front zone and nozzle. The resulting melt temperature measured at the check ring is 260–275 °C. Screw back pressure is maintained at 0.5–1.5 MPa hydraulic pressure, and holding pressure is maintained at 40–70 MPa. Injection speed is normally set between 30 mm/s and 80 mm/s, depending on gate geometry and flow length-to-thickness ratio.
Mould temperature is controlled at 70–90 °C, with no more than ±5 °C variation across the cavity surface. If the mould surface falls below 60 °C, weld-line impact and gloss transfer decline in ABS/PC components, and residual stress in the PC-rich skin can increase environmental stress cracking sensitivity. If the melt remains above 280 °C for more than 8–10 min, the PC segment undergoes measurable molecular weight reduction by hydrolysis and thermal chain scission. Production evidence is visible as silver streaks, nozzle drool, and an increase in melt volume-flow rate when the purged material is tested to ISO 1133-1:2022.
For direct-gated structural frames with nominal wall stock below 2.0 mm, the gate diameter is normally held between 0.8 mm and 1.5 mm to keep the shear rate below 100,000 s-1 and to prevent shear-induced gloss separation. In hot-runner tools, externally heated manifolds should operate at the nozzle temperature, but unheated valve-gate tips can freeze the melt surface and produce surface laminae; the valve-gate tip temperature should not fall below 240 °C. If the melt cushion fluctuates by more than 3 mm, the check ring should be inspected because non-return leakage creates inconsistent packing and anisotropic shrinkage across the part.
Mechanical Profile, Impact and Skin-Core Morphology
Reference ranges for comparable ABS/PC alloys, measured on specimens injection-moulded to ISO 294-1:2017, place the tensile yield stress between 50 MPa and 60 MPa, with tensile modulus between 2,100 MPa and 2,500 MPa, per ISO 527-2:2012. Flexural modulus measured to ISO 178:2019 falls in the same modulus window, and notched Izod impact at 23 °C is typically 35–60 kJ/m² when tested to ISO 180:2023. At -20 °C, notched Izod values fall to approximately 15–30 kJ/m², which is above general-purpose ABS but below neat PC. The product should not be assumed to reach reinforced-grade flexural modulus; a 20 wt% glass-fibre ABS/PC can exceed 4,000 MPa under ISO 178:2019, whereas unreinforced ABS PC B is not supplied as a reinforced material.
Capillary rheometry of comparable unfilled ABS/PC alloys at 260 °C and a shear rate of 1,000 s-1 gives apparent viscosity in the range of 120–200 Pa·s; at 10,000 s-1, the range falls to 30–60 Pa·s, measured to ISO 11443:2014. These values explain the material’s ability to fill thin-wall tools with lower injection pressure than unfilled PC, but they are not certified values for ABS PC B. Shear thinning is pronounced, so gate shear-rate control is essential to avoid surface defects in textured areas.
| Property | Test standard | General-purpose ABS | ABS/PC alloy reference range | Neat PC |
| Density at 23 °C | ISO 1183-1:2019 | 1.04–1.06 g/cm³ | 1.12–1.16 g/cm³ | 1.20–1.22 g/cm³ |
| Tensile yield stress | ISO 527-2:2012 | 40–50 MPa | 50–60 MPa | 60–70 MPa |
| Flexural modulus | ISO 178:2019 | 2,000–2,400 MPa | 2,100–2,500 MPa | 2,300–2,600 MPa |
| Notched Izod at 23 °C | ISO 180:2023 | 10–25 kJ/m² | 35–60 kJ/m² | 60–80 kJ/m² |
| Heat deflection under 1.80 MPa | ISO 75-2:2013 | 85–95 °C | 105–125 °C | 125–135 °C |
| Melt volume-flow rate at 260 °C/5 kg | ISO 1133-1:2022 | 20–40 cm³/10 min | 10–25 cm³/10 min | 8–15 cm³/10 min |
Table values are comparative windows for material classes, not certified values for ABS PC B. The B grade is positioned within the ABS/PC alloy reference column; its exact position can shift with PC fraction and additive package. Mould shrinkage for an unfilled ABS/PC alloy of this type is generally 0.5–0.8 % parallel and 0.6–0.9 % perpendicular to flow, measured after 48 h at 23 °C to ISO 294-4:2018. Shrinkage is anisotropic and depends on pigment loading, processing temperature, and regrind. For dimensions above 100 mm, tool trials should verify shrinkage using the actual mould because ISO 294-4:2018 plaque values do not transfer directly to complex tools with non-uniform cooling.
When Weld Lines or Living Hinges Are Present in the Part Design
Weld lines are the principal mechanical weakness in ABS/PC alloys. PC-rich skins orient parallel to the melt front and do not fully re-entangle across the meeting plane. In a two-gate automotive interior carrier tool, the knit-line zone may retain only 30–50% of the parent notched Izod value when specimens are machined across the melt join and tested to ISO 180:2023. Increasing melt temperature to the upper allowed range of 270–275 °C and reducing injection velocity to 20–40 mm/s can widen the weld-line flow path, but these changes cannot restore full parent toughness. If weld lines cannot be relocated, the part should be derated for impact at the knit plane or evaluated with instrumented puncture testing to ISO 6603-2:2023.
For living-hinge features, ABS/PC is generally less suitable than neat polycarbonate or polypropylene. The butadiene phase contributes stress whitening and low-cycle flexural crack initiation at hinge thicknesses above 0.6 mm. No universal cycle threshold is available for this grade; published data for this specific configuration are limited, and validation should be performed on the end-use hinge under the actual flex angle and temperature.
For enclosure applications requiring regulatory documentation, the supplier should provide a RoHS declaration under Directive 2011/65/EU, with XRF screening for lead, mercury, and chromium(VI) performed to IEC 62321-5:2013, IEC 62321-4:2013, and IEC 62321-7-1:2015. REACH SVHC information should be obtained under Article 33 of Regulation (EC) No 1907/2006 for each production lot. No UL 94 V-0 claim is supported for ABS PC B unless the supplier’s UL yellow card lists the exact grade; standard unfilled ABS/PC blends are often rated HB at 1.6 mm when tested to IEC 60695-11-10:2013.
| Regulatory or technical area | Assessment standard or procedure | Typical documentation |
| RoHS screening | IEC 62321-5:2013, IEC 62321-4:2013, IEC 62321-7-1:2015 | Supplier declaration |
| REACH SVHC communication | Regulation (EC) No 1907/2006, Article 33 | SVHC declaration |
| Flame classification | IEC 60695-11-10:2013 | UL yellow card |
| Residual moisture | ISO 15512:2019 | In-house QC record |
| Environmental stress cracking | ISO 22088-2:2006 | Application validation report |
Benchmarking Against Neat ABS and General-Purpose PC Grades
Compared with general-purpose ABS, ABS PC B is specified where heat distortion under load is the first shortfall of ABS. Reference data to ISO 75-2:2013 Method A place ABS/PC alloys at 105–125 °C under a 1.80 MPa flexural load, against 85–95 °C for general-purpose ABS. Notched Izod at 23 °C is also shifted upward, but the material is opaque and cannot substitute for clear ABS or clear PC in light-transmitting geometries. Compared with neat PC, the blend lowers melt temperature from the 290–310 °C window of PC to 260–275 °C, reduces melt viscosity, and improves flow length in thin-wall tools. The trade-off is weathering retention: the ABS phase causes chalking and gloss loss after outdoor exposure, so light colours require UV stabilization and validation to ISO 4892-2:2013 cycle 1.
Within the Dongguan Lidong ABS/PC series, ABS PC B is distinguished from lower-PC grades by higher heat resistance and toughness and from higher-PC grades by lower melt temperature and lower drying-related viscosity. However, because the supplier has not published PC fraction or melt flow target in third-party data collections for this exact grade, the grade-specific comparison remains subordinate to the supplier’s datasheet. Some externally available ABS/PC grades are flame-retardant or glass-fibre-reinforced; ABS PC B is not described as a reinforced grade and should not be substituted into structural applications requiring a flexural modulus above 4,000 MPa as measured to ISO 178:2019.
Thermal Degradation Begins in the PC Segment Above 280 °C
Thermal stability in ABS/PC blends is limited by the PC segment and by oxidative degradation of the butadiene phase. The upper melt limit of 280 °C is more restrictive than the lower processing limit. In injection shafts with small shot weights below 25% of barrel capacity, long residence times are likely, and the melt may reach 280–290 °C during recovery. This raises melt volume-flow rate by 10–20% after several residence cycles and lowers notched Izod, especially at -20 °C, when tested to ISO 180:2023. A melt pyrometer or insertion thermocouple should be used during nozzle purge to verify actual melt temperature rather than reading the heater bands. If the melt temperature is too high, the screw recovery speed should be reduced or the shot size matched to the barrel capacity.
Chemical incompatibility is a parallel concern. The PC segment is sensitive to alkaline cleaners, aromatic hydrocarbons, ketones, and amine-based additives. Mould release sprays, greases, and cleaners containing toluene, xylene, methyl ethyl ketone, ammonia, or hindered amine light stabilizers intended for polyolefins can induce environmental stress cracking or chain scission. Validation may be performed using ISO 22088-2:2006 under the expected in-service chemical exposure and moulded-in residual stress. After production, purging with a low-melt-mass-flow-rate high-density polyethylene or a commercial polycarbonate purging compound is used to remove heat-degraded material before shutdown.
At Regrind Fractions Above 20 wt% the MVR Shifts
Regrind usage introduces additional heat history and changes molecular weight distribution. For unfilled ABS/PC alloys, the manufacturer may allow 15–20 wt% clean regrind in non-appearance parts if the regrind is dried identically to virgin resin. Above this fraction, notched Izod, weld-line strength, and deflection temperature under load can fall outside the original specification window. Each heat history moves the melt volume-flow rate upward; incoming inspection should track melt volume-flow rate to ISO 1133-1:2022 and notched Izod to ISO 180:2023 against supplier-approved control limits. If the part is painted or electroplated, regrind content should be reduced further because rubber-phase distribution and PC migration can produce uneven adhesion.
Moisture reuptake after drying is another operational boundary. A material hopper open to ambient air at 60 %RH can reintroduce surface moisture within 30 min, so closed-loop conveying and a hopper purge with dry air are recommended. If splay appears only in later shots of a run, the moisture source may be the return-air line or the feed throat rather than the barrel temperature. Dried material should not be stored for more than 2 h outside a desiccant hopper without re-drying, although the exact re-drying interval depends on shop-floor humidity and the supplier’s moisture specification.
